1. Field of the Invention
This invention relates in general to certain new and useful improvements in gate operators and, more particularly, to improved gate operators which utilize a magnetically operable switching means at a closed or opened position, or both, for applying a force in opposition to the movement of the gate toward an end position shortly in advance of that end position and then releasing that force during movement of the gate to reduce any impact with an abutment at the end position.
2. Brief Description of the Related Art
In recent years, gate operators have become quite popular and are receiving widespread use, both for residential environments and business environments. Frequently, it is desirable to use a gate system for controlling access to a business office or otherwise to an apartment building or home. In order to provide either vehicle or pedestrian access, or both, gate operators are frequently employed and control the opening and closing movement of the gate.
Most gate operators usually employ a motor mechanism, such as an electrically or hydraulically powered motor along with one or more connecting arms which connect the motor to the gate in order to provide for an opening and closing driving movement. Moreover, the operator frequently will include some form of electronic control system for controlling the movement of the gate between the opened and closed end positions. This system typically relies upon a sensor mechanism to generate a count as, for example, the number of counts of rotation of a movable member which is correlated to the degree of movement of the gate. This count is then used in the processor of the operator in order to determine the distance of movement of the gate from one end position to the other end position.
One system of the type for controlling gate movement between two fixed end positions is more fully described in U.S. Pat. No. 4,429,264, dated Jan. 31, 1984, to Moscow K. Richmond. Other embodiments of this control system are described in U.S. Pat. No. 5,136,809, dated Aug. 11, 1992, to Moscow K. Richmond, et al, and U.S. Pat. No. 2,230,179, dated Jul. 27, 1993, to Moscow K. Richmond, et al.
The aforesaid gate operators are effectively designed to move the gate between the fixed opened and closed end positions and to stop movement of the gate when the gate reaches that fixed end position. However, because of the environment in which these gate operators are located, usually an outside environment, tolerences cannot be critical. Changes of temperature will cause the metal components to either slightly expand or contract thereby requiring a slightly longer or slightly shorter movement of the gate between fixed end positions in the same path during subsequent movements. In like manner, wear and tear on the various components will introduce other factors which preclude precise tolerance conditions. As a result, and even with those prior art gate operators which measure the distance between the fixed end positions, after a period of time, the gate will slam into an abutment at one or both of these fixed end positions.
The impact of the gate against an abutment at a fixed end position only introduces further error into the already loose tolerances, thereby worsening the possibility of impact with future opening and closing movements. In addition, the impact of the gate at these fixed end positions can ultimately result in damage to the gate and to components of the operator. At a minimum, the impact of the gate with an abutment at an end position will mar the gate, resulting in an unsightly position, not to mention the undesirable noise created by the gate when engaging an abutment at a fixed end position.
U.S. Pat. No. 4,159,599, dated Jul. 3, 1979, by Moscow K. Richmond for "Gate Opening and Closing Assembly" discloses a gate which is slidable between opened and closed positions and which uses a solenoid operated locking mechanism. U.S. Pat. No. 4,313,281, dated Feb. 2, 1982, by Moscow K. Richmond for "Gate opening and Closing Apparatus and Method" also discloses a positive locking mechanism for use in locking a gate when it reaches a gate closed position. U.S. Pat. No. 4,330,958, dated May 25, 1982, by Moscow K. Richmond for "Gate opening and Closing Assembly With Automatic Locking Means" also discloses a gate opening and closing assembly with an automatic locking means for locking the gate when it reaches a closed position.
It would be desirable to provide a system for temporarily repelling the movement of the gate toward that fixed end position to reduce the speed of the gate and, hence, the possibility of a hard impact with an abutment at a fixed end position. It would also be desirable for the system to thereafter provide a positive locking of the gate at that fixed end position, precluding an authorized opening thereof. However, to date, there has not been any effective system or any process for accomplishing this result.